EFFECT OF MODIFIER NATURE ON THE PRECONCENTRATION EFFICIENCY OF RUTIN AND QUERCETIN ON THE MAGNETITE NANOPARTICLES ; ВЛИЯНИЕ ПРИРОДЫ МОДИФИКАТОРА НА ЭФФЕКТИВНОСТЬ КОНЦЕНТРИРОВАНИЯ РУТИНА И КВЕРЦЕТИНА НА НАНОЧАСТИЦАХ МАГНЕТИТА

Flavonoids belong to a wide group of polyphenols present in many plants, flowers and seeds, vegetables and fruits. Their antioxidant action helps protect the human body from the oxidative stress, cardiovascular illnesses, inflammation, cancer and many other diseases. Researchers pay the most attention to quercetin and its glycoside rutin, which are present in many plant and food objects. One of the problems of their determination in various objects is preconcentration, which should be quick and quantitative. In the last decade, the method of magnetic solid-phase extraction (MSPE) was proposed for the preconcentration of many biologically active substances. This method is based on the phenomenon of superparamagnetism, in which magnetic nanoparticles with adsorbed analyte are separated during several tens of second from the matrix solution by a permanent magnet. In our study the magnetic nanoparticles (MNPs) of magnetite, the surface of which was modified with SiO2, SiO2 and polyethylenimine (PEI) and only PEI, are synthesized by the chemical co-precipitation method. The synthesized MNPs were characterized by the dynamic light scattering and transmission electron microscopy methods. It was shown that the magnitude and sign of the zeta potential of the MNPs were influenced by the nature of the modifier and pH of the solution. The effect of pH, the amount of sorbent, the sorption time, and the method of mixing the solution were studied and the optimal conditions for the sorption of quercetin and rutin were found. It was established that the sorption of flavonoids quantitatively occurs on magnetite, modified both with SiO2@PEI and only PEI, but the degree of extraction is higher on MNPs modified with PEI, which for quercetin and rutin was 98% and 86%, respectively. The highest degree of extraction of quercetin and rutin from the volume of 4 ml at the concentration of 10-6 - 10-5 M was achieved at the pH of 10-11, the mechanical stirring time was 10 min and the mass of sorbent was 10 mg, the desorption time was 20 ...